1. Field of the Invention
The present invention relates to an ink jet recording apparatus for recording characters and/or images on a recording material by using a recording head of ink jet type, and more particularly, it relates to an ink jet recording apparatus in which a recording head and an ink tank which are detachably interconnected are mounted on a carriage.
2. Related Background Art
A recording apparatus having a printer function, a copier function or a facsimile function or a recording apparatus used as an output device for a work station or a composite electronic equipment including a computer or a word processor is designed so that a character and/or an image is recorded on a recording sheet such as a paper or a thin plastic film on the basis of character information or image information. Depending upon a recording system, such recording apparatuses can be divided into an ink jet type, a wire dot type, a thermal type, an electrophotographic type and the like.
Among them, as a recording apparatus for in individual user, a recording apparatus of ink jet type (referred to as xe2x80x9cink jet recording apparatusxe2x80x9d hereinafter) has mainly been developed for the reasons that a sharp full-color image can be obtained at a relatively high speed and the apparatus itself can easily be made compact. General or popular ink jet recording apparatuses are of serial scanning type comprising a carriage for reciprocally shifting a recording head (mounted on the carriage) in a main scanning direction, convey means for conveying a recording material such as a recording sheet in a direction (sub scanning direction) perpendicular to the main scanning direction, and control means for controlling them. In the ink jet recording apparatus of serial scanning type, after the recording sheet is set at a predetermined recording position, main scanning of the recording head and sub scanning of the recording sheet at a predetermined pitch are repeated so that the recording is effected on the entire recording sheet by discharging ink from the recording head during the main scanning of the recording head.
As recording heads used in the ink jet recording apparatus, there are a so-called permanent recording head having a service life greater than the recording apparatus itself, and disposable recording head can be replaced or exchanged.
In the ink jet recording apparatus using the permanent head, the recording head is fixedly attached to the carriage and an ink cartridge for containing ink to be supplied to the recording head is detachably attached to the carriage. Since the recording head is designed to discharge the ink from minutes nozzles, it is very difficult to completely eliminate accidental malfunction due to clogging of nozzles with foreign matters or viscosity-increased ink or time-lapse malfunction due to deterioration of energy generating elements for generating energy for discharging the ink. Accordingly, in the ink jet recording apparatus using the permanent head, it is generally required to have special maintenance in order to ensure reliability of the recording apparatus itself by maintaining the discharging property of the recording head.
On the other hand, in the ink jet recording apparatus using the disposable head, the recording head integrally connected to the ink tank is detachably mounted on the carriage. Accordingly, when the ink is used up, since the recording head is also exchanged together with exchange of the vacant ink tank, there is almost no malfunction of the recording head. However, from the viewpoints that load in carriage movement must be reduced and that the reliability of the recording head must be maintained, increase of volume of the ink tank is limited. As a result, frequency for exchanging the ink tank is increased, with the result that the recording head is also exchange frequently, which leads to disadvantages that the running cost is increased to give burden to the user and the recording head which can still be utilized must be discarded. This is contrary to solution of the recent world wide environmental problems.
To avoid this, there has been proposed an ink jet recording apparatus in which a recording head is coupled to an ink tank in such a manner that they can be detached from each other by the user and the recording head and the ink tank are independently detachable and exchangeable with respect to the carriage, while maintaining features of a disposable head and preventing increase in the running cost and deterioration of earth environment. Further, there has been proposed an ink jet recording apparatus in which the carriage detachably mounts thereon the recording head and the ink tank in the coupled condition. With this arrangement, when ink in the ink tank is used up or consumed, the ink tank alone can be exchanged, and, if the recording head is damaged, the recording head alone can be exchanged, and both can be exchanged if necessary.
In such ink jet recording apparatuses, when the ink tank and the like is exchanged, the carriage is shifted to an exchanging position, where only the ink tank or the only the recording head or the coupled recording head/ink tank is exchanged by the user.
By the way, as mentioned above, in the recording head used in the ink jet recording apparatus, the nozzles may be clogged with the foreign matters and/or viscosity-increased ink. In a condition that the nozzles are clogged, a desired discharging property cannot be obtained, and malfunction may occur if worst comes to worst. To avoid this, in general, the ink jet recording apparatus is provided with a head recovery unit for maintaining the discharging property of the recording head by removing the foreign matters and the like from the nozzles. The head recovery unit includes a cap for capping a nozzle opening face of the recording head, and suction means for forcibly sucking the foreign matters and the like from the nozzles in a condition that the nozzle opening face is capped.
Recovery processing of the head recovery unit regarding the recording head is performed when the power supply of the ink jet recording apparatus is turned ON, before a recording operation, at a predetermined timing during the recording operation and/or after the ink tank or the recording head is exchanged.
However, in the ink jet recording apparatus of type in which the recording head and the ink tank can be exchanged independently (referred to as xe2x80x9cink jet recording apparatus of recording head/ink tank separate exchanging typexe2x80x9d hereinafter), since the recording head can be dismounted and the ink tank can also be dismounted from the carriage, the user who wished to exchange the ink tank may dismount the recording head erroneously or the user who wishes to exchange the recording head may dismount the ink tank erroneously.
Further, as mentioned above, although the recovery processing of the recording head is effected by the head recovery unit in the conventional ink jet recording apparatuses, in the ink jet recording apparatus of recording head/ink tank separate exchanging type, from the investigation by the Inventors and the like, it was found that the required recovery processing is different between when the ink tank is exchanged and when the recording head is exchanged.
For example, when the ink tank is exchanged, air may enter into a connecting portion between the ink tank and the recording head. In this case, since the air obstructs supplying of the ink from the ink tank to the recording head, the air must be removed before the recording operation is started.
Further, when the recording head is exchanged, an aging operation of the recording head itself including preliminary discharge independent from the recording must be performed and the ink viscosity of which was increased in the nozzles during the material transportation must be removed.
In any cases, the recovery processing consumes the ink, and, due to the difference in the recovery processing as mentioned above, a consumed amount of the ink becomes different between when the ink tank is exchanged and when the recording head is exchanged. Namely, the amount of ink required for the recovery processing when the ink tank is exchanged is smaller than that when the recording head is exchanged. However, in the conventional ink jet recording apparatuses, there is no judging means for judging whether the fact that the ink tank was exchanged or the fact that the recording head was exchanged, and the same recovery processing is effected, with the result that the useful ink is wasted when the ink tank is exchanged.
Further, since the frequency for exchanging the ink tank is considerably greater than the frequency for exchanging the recording tank, when the user""s convenience, an ink jet recording apparatus in which the ink tank can easily be exchanged is desired or needed.
Therefore, an object of the present invention is to provide an ink jet recording apparatus in which the fact that the user who tries to exchange an ink tank dismounts other member such as a recording head erroneously or vice versa can be eliminated.
Another object of the present invention is to provide an ink jet recording apparatus of recording head/ink tank separate exchanging type in which consumption of ink is suppressed in head recovery processing when a recording head is exchanged.
A further object of the present invention is to provide an ink jet recording apparatus of recording head/ink tank separate exchanging type in which an ink tank having exchanging frequency greater than that of a recording head can easily be effected.
The other object of the present invention is to provide an ink jet recoding apparatus including a carriage movable in a direction perpendicular to a recording material conveying direction and adapted to detachably hold a recording head and an ink tank which are coupled together in a separate exchanging permitting manner, comprising an ink tank exchanging position which is a position of the carriage where the ink tank is to be exchanged, and a recording head exchanging position which is different from the ink tank exchanging position and which is a position of the carriage where the recording head is to be exchanged.